Depth-resolved analysis of spontaneous phase separation in the growth of lattice-matched AlInN

• Published in: Journal of physics. D, Applied physics Applied physics, 2010-02, Vol.43 (5), p.055406
• Main Authors: Redondo-Cubero, A, Lorenz, K, Gago, R, Franco, N, di Forte Poisson, M-A, Alves, E, Muñoz, E
• Format: Article
• Language: English
• Subjects: Condensed matter: structure, mechanical and thermal properties; Exact sciences and technology; Low-dimensional structures (superlattices, quantum well structures, multilayers): structure, and nonelectronic properties; Physics; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties)
• ISSN: 0022-3727; 1361-6463
• DOI: 10.1088/0022-3727/43/5/055406

We report the detection of phase separation of an Al 1− x In x N/GaN heterojunction grown close to lattice-matched conditions ( x ∼ 0.18) by means of Rutherford backscattering spectrometry in channelling geometry and high-resolution x-ray diffraction. An initial pseudomorphic growth of the film was found, with good single crystalline quality, the nominal composition and very low strain state. After ∼50 nm, a critical thickness is reached at which the InN molar fraction of the films drops to ∼15% and at the same time the single crystalline quality of the films degrade drastically. This spontaneous effect cannot be ascribed to strain relaxation mechanisms since both techniques show a good single crystalline growth of the ternary under lattice matched conditions.